Three point hitches designed in accordance with ISO 730 have been used for many years and are universally accepted for attaching implements or trailing attachments to tractors or other work vehicles. The ISO 730 hitch requires precise alignment of the tractor to the implement so that the implement may be attached easily, usually by backing up the tractor. However, it may be difficult to precisely align the tractor to the implement. As a result, attaching the implement often requires two persons.
Three point hitches may be raised and lowered using switches remote from the operator station of the tractor. For example, electrical or electro-hydraulic controls for a three point hitch may be located adjacent the rear of the tractor, typically on the tractor's right or left rear fenders. These control devices make it more convenient for the operator to hook up rear mounted implements while off the tractor.
For example, a pair of switches may be located adjacent the rear of the tractor, one switch to supply a signal to a valve or valves to raise the hitch, and the other switch to supply a signal to lower the hitch. Even with the controls mounted on the fender, however, changing rear mounted implements on a three point hitch can be labor intensive because of the difficulty and time required to accurately position the tractor with respect to the implement.
Quick attaching couplers also have been developed to allow faster attachment of three point hitches to rear mounted implements from the operator station of the tractor. A quick attaching coupler may be an inverted U-shape arch that is attached to the conventional three points of a tractor hitch. The frame of a quick attaching coupler may have an upper hook with a long, tapered point and two lower coupling hooks or jaws with a latching and unlatching arrangement to hold the implement hitch pins. To hook up a quick attaching coupler to an implement, the hitch may be lowered and the tractor backed into place near the implement. Then the hitch may be raised with the hydraulic system so that the upper hook engages the upper pin on the implement. Further lifting causes the weight of the implement to force the lower hitch pins to enter the lower hooks.
Quick attach and auto hitch systems have not eliminated the inherent difficulty in attaching some implements. For example, an operator may need to back up the tractor several times to get in exactly the right position for the implement. After each attempt, the operator may need to dismount from the tractor operator station and try completing the attachment process. Additionally, quick attaching couplers may not be useful or suitable for many older attachments, nonstandard attachments, and attachments that do not sit level on the ground surface when detached. It may be difficult for an operator to complete attachment of some implements because it may require repositioning the tractor.
For these reasons, there is a need for greater operator safety and ease of use when hooking up a tractor to implements and other trailing attachments. A system is needed to make changing rear mounted implements easier for the operator. A system is needed to reduce the repeated back up positioning of the tractor to the implement, and to help accurately position the tractor. A system is needed that lets an operator complete the attachment process without repeatedly dismounting from the tractor.